Safety guard for well drilling apparatus

ABSTRACT

A safety guard for use on a well drilling rig platform including a cage protectively covering a portion of a rotary table, a portion of a well drilling rig Kelly and a portion of a rotary drive bushing, the cage being supported on the drilling rig platform and being retained in a stationary position in a drilling position of the well drilling rig apparatus wherein the rotary drive bushing is drivingly positioned in a portion of the rotary table and the Kelly is rotatingly driven by the rotary table via the drive bushing.

United States Patent 1191 Childress [451 Oct. 7, 1975 SAFETY GUARD FOR WELL DRILLING APPARATUS {22] Filed: Jan. 26, 1973 [21] Appl. No.: 326,666

[52] US. Cl. 173/165; 74/609; 175/219 7 [51] Int. Cl E2lb 41/00 [58] Field of Search 173/l65167,

[56] References Cited 3,270,810 9 1966 Johnston 166/81 x 3,322,198 5/1967 McHenry 166/81 FOREIGN PATENTS OR APPLICATIONS 459,065 4/1928 Germany 74/609 Primary ExaminerErnest R. Purser Assistant Examiner-William F. Pate, III Attorney, Agent, or Firm-Dunlap & Codding [57] ABSTRACT A safety guard for use on a well drilling rig platform including a cage protectively covering a portion of a rotary table, a portion of a well drilling rig Kelly and a portion of a rotary drive bushing, the cage being supported on the drilling rig platform and being retained in a stationary position in a drilling position of the well drilling rig apparatus wherein the rotary drive bushing is drivingly positioned in a portion of the rotary table and the Kelly is rotatingly driven by the rotary table via the drive'bushing.

14 Claims, 10 Drawing Figures U.S. Patent Oct. 7,1975 Sheet 1 of 3 3,910,359

SAFETY GUARD FOR WELL DRILLING APPARATUS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to safety devices and, more particularly, but not by way of limitation, to a safety guard for well drilling rig apparatus.

2. Description of the Prior Art Various cage or shield type devices have been constructed in the past to provide a cover protectively encompassing some object for either protecting the object or preventing other objects from engaging the protected object for a variety of reasons. Protective devices and controls have become of particular concern in recent years primarily due to the ever increasing concern for providing safe working environments.

In well drilling rig operations, such as in an oil well drilling .rig operation, for example, protection devices are particularly required and useful due to the large number of operations and the relative size of the various pieces of equipment handled via the oil well drilling rig personnel. In an oil well drilling rig operation, it is necessary to drivingly rotate a pipe drill string extending through a platform into the earth during the drilling operations of the well drilling rig apparatus. In many instances, some of the equipment such as the chains or hoses or the like, for example, have become entangled in various portions of the rotating equipment utilized in the oil well drilling rig operation, the entanglement resulting in serious injuries and, in some instances, the death of oil drilling rig personnel.

The U.S. Pat. No. 2,719,025, issued to Stone, disclosed a drill collar held in place via slips and a safety collar located above the slips, a second safety collar also being attached to the drill collar. The Stone patent also disclosed a single safety collar construction, the double and the single safety collar constructions each providing a safety collar for preventing the loss of the drill collar. Since the so-called safety collars of the Stone patent were secured to the drill collar, these safety devices were rotated during the drilling operations and were primarily constructed to protect the equipment. A similar type of well pipe protector was disclosed in the US. Pat. No. 3,051,532, issued to C01- lett, various drill pipe protectors also being disclosed in the U.S. Pat. Nos. 2,789,870, issued to I-Ianes; 3,019,063, issued to Collett; and 2,959,453, issued to Jacobs. The US. Pat., No. 3,612,627, issued to Fuller, disclosed a cylindrical collar adapted to be clamped onto a drill pipe which utilized a split casing type of construction secured in an assembled position via a pin.

The US. Pat. No. 3,063,509, issued to Guier, disclosed an apparatus for handling strings of drill pipe in such a manner that the drilling rig personnel were not required to be on the derrick floor near the elevators Orner patent was extended about the auger type of drilling element and was telescoped inwardly as the apparatus was moved downwardly drilling the hole in the earth.

SUMMARY OF THE INVENTION An object of the invention is to provide a safety guard for protectively guarding portions of a well drilling rig rotary table. I

Another object of the invention is to provide a safety guard for protectively guarding portions of a rotary table and a rotary drive bushing of a well drilling rig.

One other object of the invention is to provide a safety guard which is supported in a stationary position protectively guarding the rotary drive bushing and portions of the rotary table of a well drilling rig.

Yet another object of the invention is'to provide a safety guard protectively guarding the rotary drive bushing and portions'of the rotary table. capable of being lockingly secured in an assembled position, yet removable in a quick and efficient manner.

Another object of the invention isto provide a safety guard substantially increasing personnel safety in well drilling rig operations.

A still further object of the invention is to. provide a safety guard which is economical in the constructionand the operation thereof.

Other objects and advantages of the invention will be evident from the following detailed description when read in conjunction with the accompanying drawings which illustrate'preferred embodiments of the invention.

I BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of the safety guard of the present invention diagrammatically showing portions of a well drilling rig platform and rotary table.

FIG. 2 is a top plan view of the apparatus of FIG. 1.

FIG. 3 is a fragmentary, partial cut-away view similarto FIG. 1, but showing a section through the safety guard of the present invention, a side elevational view of a typical rotary drive bushing, a fragmentary side elevational view of a portion of the Kelly, and a partial side elevational view, partial sectional view of the rotary table.

during a substantial portion of the operation, except for for a Kelly joint utilized with rotary drilling rigs, the

collars being provided with pins and chains for securing the collar in'an assembled position about the apparatus.

The U5. Pat. No. 1,143,257, issued to Double; the US.

1,141,927, issued to Boyd; and the US. Pat. ,No.

1,679,14l,-issued to Gartin, .each disclosed various ap- FIG. 4 is a top plan view of the platform extension of the present invention, the platform extension supportingly engaging a lower end portion of the safety guard (not shown in FIG. 4) in one operational position thereof. FIG. 5 is a bottom plan view of the safety guard of FIGS. 1, 2 and 3.

FIG. 6 is a side elevational view of the safety guard of FIGS. 1, 2, 3 and 5.

FIG. 7 is a fragmentary, enlarged plan view of a portion of the upper end of the safety guard of FIGS. 1, 2, 3, 5 and 6, showing oneof the vertical rods and one of =thehorizontal rodsin a locked position; Pat. No. 1,644,026, issued to Mock; the US. Pat. No.

guard constructed in accordancewith the present in- FIG. 8 is a side elevational view of a modified safety vention.

FIG. 9 is a top plan view of the modified safety guard of FIG. 8.

FIG. is a partial, enlarged, sectional view of the modified safety guard. of FIGS. 8 and 9 showing a portion of the interlocking engagement between the first and the second cage segments.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings in general, and to FIGS. 1, 2 and 3 in particular, shown therein and designated by the general reference numeral 10 is a safety guard constructed in accordance with the present invention, the safety guard 10 being supported on a well drilling rig platform 12 and constructed to protectively guard por tions of the well drilling rig apparatus during portions of the well drilling rig operations. The safety guard 10 is, more particularly, constructed to protectively encompass portions of a rotary drive bushing 14, portions of a rotary table 16 and a portion of a well drilling rig Kelly 18 disposed through a portion of the rotary table 16 in a drilling position of the well drilling rig apparatus and in one operating position of the safety guard 10, as shown in FIGS. 1, 2 and 3 and as will be described in greater detail below.

A typical oil well drilling rig includes a derrick supported on'the well drilling rig platform (a portion of the well drilling rig platform being shown in FIG. 1 and designated via the general reference numeral 12) and a crown block generally having a plurality of pulleys or the like is connected to the top portion of the derrick supporting structure, a plurality of cables extending from a powered draw works mounted on the well drilling rig platform 12 or generally near the well drilling rig platform 12 over the pulleys in the crown block to flexibly suspend a traveling block in the derrick. The traveling block generally includes a traveling block hook that is pivotally connected therewith and bails are suspended from the traveling block hook.

A drill bit is secured to one end of a string of heavy drill pipe and a length of rod having a substantially square or polygonal form is connected to the upper end of the string of drill pipe, the rod having the square or polygonal cross-section being referred to generally in the art as a grief stem or Kelly such as the portion of the Kelly 18, shown in FIGS. 1, 2 and 3. The string of drill pipe and the Kelly 18 are disposed through an axial opening 20 formed in the rotary table 16, as shown in FIG. 3, an upper end portion 22 of the axial opening 20 being shaped to receive and rotatingly engage slips 24 on the lower end portion of the rotary drive bushing 14. It should be noted that, in some forms, the axial opening through a rotary table is sized to directly receive and drivingly engage the Kelly and, the well drilling rig apparatus, in this instance, does not include a rotary drive bushing, such as the rotary drive bushing 14, for example, the present invention being utilized in this particular form to protectively guard portions of the rotary table and portions of the Kelly generally near the rotary table in a drilling position of the well drilling rig operations, in a manner which will be apparent to those skilled in the art in view of the detailed description of the invention herein.

The Kelly 18 is generally connected by tool joints (a fragmentary portion of one of the tool joints being shown in FIGS. 1 and 3 and designated therein via the general reference numeral 26). The Kelly 18 and the string of drill pipe connected thereto are generally sup ported on traveling block hooks connected to a swivel, the swivel being secured to the string of drill pipe and the traveling block hooks being connected to the swivel, as generally mentioned before.

The rotary drive bushing 14 has an axial opening formed therethrough (not shown) shaped to matingly and drivingly receive and engage the Kelly 18 in a manner enabling the rotary table 16 to impart driving rotation to the Kelly 18 and also permitting longitudinal or axial sliding action between the Kelly 18 and the rotary drive bushing 14 in a drilling position of the well drilling rig operation. More particularly, the slips 24 of the rotary drive bushing 14 are shaped to matingly fit within the upper end portion 22 of the axial opening 20 through the rotary table 16.

The rotary table 16 is connected to a power drive (not shown) via a drive connection28, as diagrammatically shown in FIGS. 1 and 3. The power drive (not shown) drivingly rotates a portion of the rotary table 16 via the drive connection 28, the rotary table 16 imparting rotary motion to the string of drill pipe and, more particularly, to the Kelly 18 via the interconnection between the rotary drive bushing 14 and the Kelly 18 and the interconnection between the slips 24 of the rotary drive bushing 14 and the rotary table 16 in a manner well-known in the art and as generally described in such reference books as Petroleum Engineering Drilling and Well Completions by Carl Gatlin, published by Prentice-Hall Incorporated, Englewood Cliffs, New Jersey, for example. The use and various aspects of the operations of the well drilling rig apparatus, including various structural details are also disclosed in the various prior art patents referred to before in the description of the prior art.

More particularly, and as shown in FIGS. 1 and 3, the rotary table 16 is supported on a support structure 30 (fragmentarily shown in FIGS. 1 and 3) and includes the drive connection 28 connecting the power drive units (not shown) to a drive gear (not shown) located within a portion of the rotary table 16. The drive gear (not shown) is gearingly connected to the rotating table portion 32 of the rotary table 16 and drivingly rotates the rotating table portion 32 about a rotational axis substantially aligned with the axial axis of the opening 20 through the rotary table 16, in a manner well-known in the art and as shown and described in various aspects in the United States Patents referred to before in the description of the prior art, rotary tables being commercially available from such suppliers as Oil Well Supply Company, a division of United States Steel Corporation, having a place of business in Tulsa, Oklahoma, for example. i

As generally known by the various United States Patents referred to before in the description of the prior art, various forms of rotary tables are available in the industry. Some of the commercially available rotary tables including a framework, such as the framework 34 shown in FIGS. 1, 2 and 3, the framework 34 cooperating to encompass a portion of the rotary table 16 and having an opening 36 formed through the top portion 38 of the framework 34 providing communication with fore. As shown in FIGS. 1, 2 and 3, the framework 34 is supported on the support structure 39 such that the top portion 38 is substantially coplanar with and forms a portion of the well drilling rig platform 12 along with the fragmentary platform portions 40 shown in the drawings. Thus, the top portion 38 of the framework 34 and the platform portions 40 are sometimes generally referred to herein as the well drilling rig platform'lZ.

The particular rotary table 16, illustrated in FIGS. 1, 2 and 3, is disposed a distance below the Opening 36 formed through the well drilling rig platform portion 12 (through the top portion 38 of the framework 34), the rotary table 16 being supported generally beneath the opening 36 via the support structure 30. In other forms of commercially available rotary tables and installations thereof on well drilling rig platforms, the rotary tables or portions thereof are disposed above the well drilling rig platform or supported on a portion thereof. It is to be noted that the particular construction of the rotary table, the well drilling rig platform, the Kelly and the rotary drive bushing do not form a part of the present invention, and the safety guard of the present invention is constructed to be utilized in cooperation with rotary tables of various constructions, shapes and sizes. However, the safety guard 10 is described herein with reference to the rotary table 16 having the framework 34 disposed thereabout to clarify and illustrate certain aspects of the construction and the operation of the safety guard 10 with respect to one particular rotary table 16, it being specifically understood that the safety guard 10 is not limited to use in connection with a rotary table of this particular type of construction or this particular type of installation on a well drilling rig.

Referring more particularly to the construction of the safety guard 10 of the present invention, the safety guard 10 includes a cage 44 having a cage wall 46 with an upper end 48, a lower end 50 and a cage opening 52 formed therethrough intersecting the upper and the lower ends 48 and 50. As shown more clearly in FIGS. 2, 3 and 5, a cage plate 54 is connected to the upper end 48 of the cage 44 and extends generally over and closes a portion of the cage opening 52 at the upper end 48 thereof, a Kelly opening 56 being formed through a central portion of the cage plate 54. The Kelly opening 52 is sized to receive and encompass a portion of the well drilling rig Kelly 18, as shown more clearly in FIGS. 2 and 3, thereby providing communication through the cage plate 54 with the cage opening 52 for extending a portion of the well drilling rig Kelly 18 through the Kelly opening 56. More particularly, the cage 44, the cage opening 52 and the Kelly opening 56 are each constructed and positioned in an operating position of the safety guard 10 such that a portion of the well drilling rig Kelly 18 is disposed through the Kelly opening 56, through the cage opening 52, through the opening 38 in the well drilling rig platform 12 and subsequently through a portion of the rotary table 16, the cage opening 52 and the Kelly opening 56 being in communication with the opening 38 and a portion of the rotary table 14, for reasons which will be made more apparent below.

The cage wall 46 forms an outer peripheral surface 58 and an inner peripheral surface 60 of the cage 44, as shown more clearly in FIGS. 2, 3 and 5. In one preferred form, the cage 44 is generally cylindrically shaped and the inner peripheral surface 60 forms the cage opening 52 surrounding a portion of'the Kelly 18,

a portion of the rotary drive bushing 16 and a portion of the opening 38 through the well drilling rig platform 12, in an assembled position of the safety guard 10 and in a drilling position of the well drilling rig apparatus.

As shown more clearly in FIG. 2, the Kelly opening 56 through the cage plate 54 has a diameter larger than the average diameter of the well drilling rig Kelly 18 and smaller than the diameter of the rotary drive bushing 14, in one preferred form. Thus, in one operating position of the safety guard 10, a portion of the Kelly 18 extends through the Kelly opening 56 and the rotary drive bushing 14 is disposed generally within the cage opening 52 below the cage plate 54, the slips 24 of the rotary drive bushing 14 being positioned in driving engagement with the upper end position 22 of the axial opening 20 through the rotary table 16, as shown more clearly in FIG. 3. In this manner, the safety guard 10 remains in an assembled position about the rotary drive bushing 14 during those aspects of the well drilling rig operations wherein the string of drill pipe is pulled upwardly above the well drilling rig platform 12, a portion of the rotary drive bushing 14 engaging a portion of the cage plate 54 and supporting the cage 44 thereon during those aspects of .the well drilling rig operations wherein the string of drill pipe is pulled from the borehole. The safety guard 10 is removably secured about portions of the Kelly 18 and the rotary drive bushing 14 and .thus the safety guard 10 can also be removed or disassembled during this portion of the well drilling rig operations when desired in a particular application. It should also be noted that the reduced size of the Kelly opening 56 with respect to the cage opening 52 provides a minimum clearance generally designated in FIG. 2 via the reference numeral 62) between the portions of the cage plate 54 formed via the Kelly opening 56 and the portion of the Kelly 18 extending therethrough to substantially reduce the opportunity of chains and hoses and the like being inadvertently dragged over and dropped through the upper end 48 of the safety guard 10 resulting in the chain or hose or the like becoming entangled in a portion of the Kelly 18 or the rotary drive bushing 14 during the well drilling rig operations. I

To facilitate the assembly and removal of the safety guard 10 from about the Kelly 18 and the rotary drive bushing 14, the cage- 44 is, more particularly, constructed of a first cage segment 66 and a second cage segment 68, the first and the second cage segments 66 and 68 each comprising approximately one-half of the cage 44, in the one preferred embodiment of the safety guard 10 shown in FIGS. 1 through 7. The first cage segment 66 includes an arcuately shaped wall segment 70 having an upper end 72 and a lower end 74, the wall segment 70 forming an outer peripheral surface 76 and an inner peripheral surface 78. As shown more clearly in FIG. 5, the wall segment 70 of the first cage segment 66 has opposite edges 80 and 82 extending generally between the upper end 72 and the lower end 74, the opposite edges 80 and 82 forming mating surfaces matingly engageable with portions of the second cage segment 68, in one preferred form and in a manner to be described in greater detail below.

The second cage segment 68 is constructed similar to the first cage segment 66 and includes an arcuately shaped wall segment 84 having an upper end 86 and a lower end 88. The wall segment 84 forms an outer peripheral surface 90 and an inner peripheral surface 92 terminating with opposite edges 94 and 96 forming mating surfaces engageable with the mating surfaces formed via the opposite edges 80 and 82 of the first cage segment 66, in an assembled position of the first and the second cage segments 66 and 68, as shown in the drawings.

The safety guard 10 includes a lock assembly 98 for lockingly securing the first and the second cage segments 66 and 68 in an assembled position wherein a portion of the Kelly 18 generally near the rotary drive bushing 14 extends through the Kelly opening 56 and a portion of the rotary drive bushing 14 is disposed within a portion of the cage opening 52, as shown in FIGS. 1, 2 and 3. The lock assembly 98 is constructed so that the first and the second cage segments 66 and 68 can be secured in a locked position locking the cage 44 in an assembled position and so that the first and the second cage segments 66 and 68 can be disassembled in a relatively fast and efficient manner. More particularly, the lock assembly 98 includes a first and a second vertical hinge assembly 100 and 102 and a first and a second horizontal hinge assembly 104 and 106, as shown in FIGS. 1, 2, 3, 6 and 7.

The first and the second vertical hinge assemblies 100 and 102 include a plurality of first hinge elements 108, two of the first hinge elements 108 being, more particularly, secured to the outer peripheral surface 76 of the wall segment 70 generally adjacent the edge 80 of the first cage segment 66 and two of the first hinge elements 108 being secured to the outer peripheral surface 76 of the wall segment 70 generally adjacent the edge 82 of the first cage segment 66. Each pair of the first hinge elements 108, secured adjacent the edges 80 and 82, are spaced a predetermined distance apart and extend a distance generally perpendicularly from the respective edges 80 and 82. As shown in FIG. 3, each of the first hinge elements 108 has a hinge opening 110 extending therethrough. The first hinge elements 108 are each positioned on the outer peripheral surface 76 of the first cage segment 66, generally adjacent the edges 80 and 82, so that the edges 80 and 82 can matingly abut the edges 94 and 96 of the second cage segment 68 in an assembled position of the cage 44, in a manner to be described in greater detail below;

The first and the second vertical hinge assemblies 100 and 102 also include a plurality of second hinge elements 112, two of the second hinge elements 112 being secured to the outer peripheral surface 90 of the second cage segment 68 generally adjacent the edge 94 and two second hinge elements 112 being secured to the outer peripheral surface 90 of the second cage segment 68 generally adjacent the edge 96. As shown in FIG. 3, each of the second hinge elements 112 has a hinge opening 1 14 formed therein and extending therethrough. More particularly, the second hinge elements 112 adjacent the edge 94 of the second cage segment 68 are spaced a predetermined distance apart and extend a distance from the edge 94 such that, in an assembled position of the first and the second cage segments 66 and 68 wherein the edges 80 and 82 of the first cage segment 66 but the edges 94 and 96 respectively of the second cage segment 68, the hinge openings 110 and 114 through the first and the second hinge elements 108 and l 12 of the first vertical hinge assembly 100 are aligned and the hinge openings 110 and 114 through the first andthe second hinge elements 108 and 112 of the second vertical hinge assembly 102 are aligned, for reasons which will be made more apparent below.

As shown more clearly in FIGS. 2 and 5,'the cage plate 54, more particularly, includes a first plate segment 116 and a second plate segment 118. The plate segments 116 and 1 18 cooperate to form the cage plate 54 in an assembled position of the cage 44 as shown in the drawings. I

The first plate segment 116 is, more particularly, secured to the upper end 72 of the first cage segment 66 and forms a plate edge 120 extending diametrically across the upper end portion of the first cage segment 66 generally between the opposite edges and 82. An arcuately shaped portion 122 is formed through a central portion of the plate edge 120, the arcuately shaped portion 122 cooperating to form a portion of the Kelly opening 56 in an assembled position of the cage 44.

The second plate segment 118 is, more particularly, secured to the upper end 86 of the second cage segment 68, the second plate segment 118 forming a plate edge 124 extending diametrically across the second plate segment 118 generally between the opposite edges 94 and 96. An arcuately shaped portion 126 is formed through a central portion of a plate edge 124, the arcuately shaped portion 126 cooperating to form a portion of the Kelly opening 56 through the edge plate 54 in an assembled position of the cage 44, in a manner to be made more apparent below.

Shown more clearly in FIGS. 1, 2, 3 and 7, the first and the second horizontal hinge assemblies 104 and 106 each include one first plate hinge element 128 formed on top of the first plate segment 116 generally adjacent the plate edge thereof, a plate hinge opening 130 being formed through each of the first plate hinge elements 128. The first plate hinge elements 128 are spaced a distance apart and, more particularly, the first plate hinge element 128 of the first horizontal hinge assembly 104 is formed on one side of the arcuately shaped portion 122 and the first plate hinge element 128 of the second horizontal hinge assembly 106 is formed on the opposite side of the arcuately shaped portion 122.

The first and the second horizontal hinge assemblies 104 and 106 each include one second plate hinge element 132 formed on the top of the second plate segment 118 generally adjacent the plate edge 124 and extending a distance therefrom, a plate hinge opening 134 being formed through each of the second plate hinge elements 132. The second plate hinge elements 132 are spaced at distance apart and, more particularly, the second plate hinge element 132 of the first horizontal hinge assembly 104 is formed on one side of the arcuately shaped portion 126 and the second plate hinge element 132 of the second horizontal hinge assembly 106 is formed on the opposite side of the arcuately shaped portion 126.

In an assembled position of the cage 44, the plate edges 120 and 124 of the first and the second plate segments 1 16 and 118 matingly abut such that the first and the second plate segments 116 and 118 cooperate to form the cage plate 54, the arcuately shaped portions 122 and 126 being positioned in alignment in an abutting position of the plate edges 120 and 124 and cooperatingly forming the Kelly opening 56 through the cage plate 54. The first and the second plate hinge elements 128 and 132 are each positioned such that, in an assembled position of the cage 44, the plate hinge openings 130 and 134 through the first and the second plate hinge elements 128 and 132 of the first horizontal hinge assembly 104 are aligned, and the plate hinge openings 130 and 134 through the first and the second plate hinge elements 128 and 132 of the second horizontal hinge assembly 106 are aligned, for reasons which will be made more apparent below.

The first and the second vertical hinge assemblies 100 and 102 each include a vertical rod 136 and 138, respectively, an angled portion 140 being formed on one end portion of the vertical rod 136 and an angled portion 142 being formed on one end of the vertical rod 138. The vertical rods 136 and 138 are each sized such that, in an assembled position of the first and the second cage segments 66 and 68 wherein the hinge openings 110 and 114 of the first and the second hinge elements 108 and 112 are aligned, the end of the vertical rod 136, opposite the angled portion 140 end, is insertable through the hinge openings 110 and 114 of the first vertical hinge assembly 100 an the end of the vertical rod 138, opposite the angled portion 142 end thereof, is insertable through the hinge openings 110 and 114 of the second vertical hinge assembly 102. More particularly, the vertical rod 136 is insertable through the hinge openings 110 and 114 in a general direction 144 to a position wherein the angled portion 140 engages a portion of one of the first hinge elements 108 of the first hinge assembly 100, thereby limiting the movement of the vertical rod 136 in a direction 144 through the hinge openings 110 and 114 and positioning the vertical rod 136 in an assembled position in the first vertical hinge assembly 100 locking the edge 80 of the first cage segment 66 to the edge 94 of the second cage segment 68.

In this position, the first and the second cage segments 66 and 68 are each pivotally locked or connected via the vertical rod 136, the first and the second cage segments 66 and 68 each being pivotally movable in pivot directions 146 and 148 about the vertical rod 136 moving each of the first and the second cage segments 66 and 68 in directions separating the first and the second cage'segments 66 and 68. In the pivotally separated position of the first and the second cage segments 66 and 68, the edges 82 and 96 of the first and the second cage segments 66 and 68 respectively are spaced a distance apart, and the first and the second cage segments 66 and 68 are positionable about the Kelly 18 and the rotary drive bushing 14 via the opening resulting from separation between the edges 82 and 96 of the first and the second cage segments 66 and 68, the first and the second cage segments 66 and 68 being then pivotally movable in directions 150 and 152 about the vertical rod 136 pivotally moving the first and the second cage segments 66 and 68 to an assembled position wherein the mating edges 80 and 82 of the first cage segment 66 matingly abut the mating edges 94 and 96 of the second cage segments 68 to position the cage 44 in an assembled position, in one operational embodiment of the safety guard 10.

After the first and'the second cage segments 66 and 68 have been pivoted to an assembled position, the end of the vertical rod 138, generally opposite the angled portion 142 end thereof, is then inserted lengthwise through the hinge openings 110 and 114 of the second vertical hinge assembly 102. More particularly, the vertical rod 138 is moved through the hinge openings 110 and 114 of the second hinge assembly 102 in a general direction 154 to a position wherein a portion of the angled-portion 142 end thereof engages one of the first hinge elements 108 of the second hinge assembly 102, generally adjacent the upper end 46 of the cage 44, thereby limiting the movement of the vertical rod 138 in the direction 154 through the hinge openings and 114 and positioning the vertical rod 138 in an assembled position.

After the vertical rods 136 and 138 have been assembled through the hinge openings 110 and 114 of the first and the second vertical hinge assemblies 100 and 102, the first and the second cage segments 66 and 68 are each locked in an assembled position via the two vertical rods 136 and 138. From the foregoing, it will be apparent to those skilled in the art that the vertical rod 138 could be inserted in an assembled position within the second hinge assembly 102 and the first and the second cage segments 66 and 68 could each be pivoted about the pivotal connection therebetween formed via the vertical rod 138, in a manner and for reasons similar to that described before with respect to the vertical rod 136 and the first vertical hinge assembly 100.

The first horizontal.hinge assembly 104 includes a horizontal rod 156 having an angled portion 158 formed on one end thereof and the second horizontal hinge assembly 106 includes the horizontal rod 160 having an angled portion 162 formed on one end thereof. The end of the horizontal rod 156, opposite the angled portion 158 end thereof, is insertable through the aligned plate hinge openings and 134 of the first horizontal hinge assembly 104, and the end portion of the horizontal rod 160, opposite the angled portion 162 thereof, is insertable through the aligned plate hinge openings 130 and 134 of the second horizontal hinge assembly 106 to secure a portion of the first and the second cage segments 66 and 68 in an assembled position. More particularly, the horizontal rod 156 is insertable through the plate hinge openings 130 and 134 of the first horizontal assembly 104 in a general direction 164 to a position wherein the angled portion 158 engages the first plate hinge element 128 limiting the movement of the horizontal rod 156 in the direction 164 through the plate hinge openings 130 and 134, and the horizontal rod is insertable through the plate hinge openings 130 and 134 of the second horizontal hinge assembly 106 in a general direction 166 to a position wherein the angled portion 162 thereof engages the first plate hinge element 128 limiting the movement of the horizontal rod in the direction 166 through the plate hinge openings 130 and 134, thereby positioning the horizontal rods 156 and 160 in an assembled position within the first and the second horizontal hinge assemblies 104 and 106, as shown more clearly in FIGS. 1, 2, 6 and 7.

As mentioned before, one of the vertical rods 136 and 138 can be inserted in an assembled position in one of the first and the second vertical hinge assemblies 100 and 102 so that the first and the second cage segments 66 and 68 are pivotally connected via the first or the second hinge assembly 100 or 102. In one other preferred operational embodiment, the first and the second vertical hinge assemblies 100 and 102 are constructed to lockingly secure the first and the second horizontal hinge assemblies 104 and 106 in a locked, assembled position. In this form of the invention, the horizontal rods 156 and 160 are inserted in an assembled position prior to inserting the vertical rods 136 and 138 in an assembled position with the first and the second vertical hinge assemblies 100 and 102, respectively, or, in one other operational form, the vertical rods 136 and 138 are each raised a distance in a generally upwardly direction 168 and 170, respectively, to facilitate the insertion of the horizontal rods 156 and 160, for reasons and in a manner to be described in greater detail below.

In the operational embodiment of the invention where the first and the second horizontal hinge assemblies 104 and 106 are assembled prior to the assembly of the first and the second vertical hinge assemblies 100 and 102, the first and the second cage segments 66 and 68 are each positioned about the rotary dn've bushing 14 and about a portion of the Kelly 18, the first and the second cage segments 66 and 68 being moved to an assembled position wherein the mating edges 80 and 82 of the first cage segment 66 matingly abut the respective mating edges 94 and 96 of the second cage segment 68. In this position, the plate edges 120 and 124 are also positioned in a matingly abutting position, and a portion of the well drilling rig Kelly 18 extends through the Kelly opening 56 formed via the arcuately shaped portions 122 and 126 formed in the plate edges 120 and 124, respectively, a portion of the rotary drive bushing 14 being disposed within a portion of the cage opening 52, thereby assembling the first and the second cage segments 66 and 68 in an initial assembled position about the rotary drive bushing 14 and the Kelly 18.

In this initial, assembled position of the first and the second cage segments 66 and 68, the horizontal rod 156 is inserted through the aligned plate hinge openings 130 and 134 of the first horizontal hinge assembly 104 to a position wherein the angled portion 158 thereof engages the first plate hinge element 128 and the horizontal rod 160 is inserted through the aligned plate hinge openings 130 and 134 of the second horizontal hinge assembly 106 to a position wherein the angled portion 162 thereof engages the first plate hinge element 128 of the second horizontal hinge assembly 106. In this position, the horizontal rods 136 and 138 cooperate to partially secure the first and the second cage segments 66 and 68 in an assembled position via the first and the second horizontal assemblies 104 and After the horizontal rods 156 and 160 have been assembled in the first and the second horizontal hinge assemblies 104 and 106, the vertical rod 136 is then inserted through the aligned hinge openings 110 and 114 of the first vertical hinge assembly 100 to a position wherein the angled portion 140 thereof engages the first hinge element 108 of the first vertical hinge assembly 100, the vertical rod 136 being sized and positioned such that the angled portion 140 thereof is disposed generally adjacent the angled portion 158 formed on the horizontal rod 156 of the first horizontal hinge assembly 104 in an assembled position. More particularly, the angled portion 140 of the vertical rod 136 is sized to extend a distance above the first hinge element 100 of the first vertical hinge assembly 100 in an assembled position thereof and is disposed generally near and adjacent the angled portion 158 formed on the horizontal rod 156 of the first horizontal hinge assembly 104, the angled portion 140 being positioned to engage and limit the movement of the horizontal rod in a direction 172, thereby preventing the horizontal rod 156 from being removed from the first horizontal hinge assembly 104 in an assembled position of the vertical rod 136 of the first vertical hinge assembly 100.

The vertical rod 138 is then disposed through the aligned hinged openings 1 10 and 1 14 of the second vertical hinge assembly 102 in a general direction 144 to a position wherein the angled portion 142 of the vertical rod 138 engages the first hinge element of the first vertical hinge assembly 100 thereby positioning the vertical rod 142 in a predetermined assembled position. The vertical rod 138 is also sized such that, in an assembled position thereof, the angled portion 138 extends a distance above the first hinge element 100 of the second hinge assembly 102 and is disposed generally near and adjacent the angled portion 162 of the horizontal rod 160, the angled portion 142 of the vertical rod 138 being positioned to engage the angled portion 162 of the horizontal rod 160 limiting the movement of the horizontal rod 160 in a direction 174 thereby preventing the horizontal rod 160 from being removed from the second horizontal hinge assembly 106 in an assembled position of the second vertical hinge assembly 102.

It should be noted that, in those applications where the vertical rods 136 and 138 are inserted in the first and the second vertical hinge assemblies 100 and 102 prior to inserting the horizontal rods 156 and 160, the vertical rods 136 and 138 are each lifted in a generally upwardly direction 168 and 170, respectively, a sufficient distance so that the angled portions and 142 do not interfere with the insertion of the horizontal rods 156 and 160. The vertical rods'1-36 and 138 are each then lowered in directions 144 and 154 and secured in an assembled position in a'manner to be described in greater detail below.

A chain 176 is secured to one end thereof to a portion of the cage plate 54 and, more particularly, to a portion of the first plate segment 116, the opposite end of the chain 176 being removably connectable to a portion of the angled portion 140 of the vertical rod 136 limiting the movement of the vertical rod 136 in a direction 168, thereby preventing the vertical rod 136 from being withdrawn from the first vertical hinge assembly '100 when connected thereto. One end of a chain 178 is also secured to a portion of the cage plate 54 and, more particularly, to the portion of the second plate segment 118, the opposite end of the chain 178 being removbly connectable to a portion of the angled portion 142 of the vertical rod 138 limiting the movement of the vertical rod 138 in a direction 170 and preventing the vertical rod 138 from being removed from an assembled position within the second vertical hinge assembly 102.

Thus, the chains 176 and 178 are each removably connectable to one of the vertical rods 136 and 138, respectively, preventing the vertical rods 136 and 138 from being removed, and the angled portions 140 and 142 of the vertical rods 136 and 138 are each positioned to engage one of the angled portions 158 and 162 of the horizontal rods 156 and preventing the inadvertent removal of the horizontal rods 156 and 160 during the operation of the safety guard 10 of the present invention. The lock assembly 98, which includes the first and the second vertical hinge assemblies 100 and 102 and the first and the second horizontal hinge assemblies 104 and 106, securedly locks the first and the second cage segments 66 and 68 in an assembled position in a manner substantially preventing the inadvertent disassembly of the safety guard during the operation of the present invention, yet in'a manner such that the first and the second cage segments 66 and 68 are easily separated and disassembled in a relatively fast and efficient mannerv As shown in FIGS. 1, 3 and 6, the safety guard 10 also includes a plurality of openings 180 having a Wire screen 182 secured over each opening 180. The openings 180 are each formed in the cage wall 46 and spaced circumferentially thereabout so the operation of the well drilling rig apparatus covered via the safety guard 10 can be observed in an assembled position of the safety guard 10.

As generally mentioned before, the lower end 48 of the cage 44 is constructed to be supported on a portion of the well drilling rig platform 12 or the portion 38 thereof in an assembled position of the safety guard 10 so that the safety guard 10 is supported in a stationary, non-rotating position about the rotary drive bushing 14 and about a portion of the well drilling rig Kelly 18 during one aspect of the operation of the safety guard 10. In some applications, the opening 36 throughthe portion 38 of the Well drilling rig platform 12 is relatively large and, since a cage constructed to be supported on the portion 38 of the well drilling rig platform 12 would have a diameter larger than the diameter of the opening 36, the overall size and weight of the safety guard 10 would be substantially increased. The increased weight and size of the safety guard 10, of course, lessens the maneuverability of the safety guard 10 and does not provide any substantial increased protection with respect to guarding portions of the rotary table 16, the well drilling Kelly 18 and the rotary drive bushing 14. Thus, in these applications, it has been found desirable to utilize a platform extension 184, having a portion connected to the well drilling rig platform 12 or portion 38 thereof and a portion extending over the opening 36 through the well drilling rig platform 12 thereby encompassing a portion of the opening 36 and effectively reducing the opening 36 diameter.

In a preferred form, the platform extension 184 has a shape substantially corresponding to the shape of the opening 36 and includes an opening 186 formed through a portion thereof providing communication with the rotary table 16, the portion of the platform extension 184 extending between the rotary table opening 186 therein and the outer peripheral surface thereof substantially covering a portion of the opening 36 through the well drilling rig platform 12 generally adjacent the outer periphery thereof. In one preferred form, as shown more clearly in FIGS. 2 and 4, the platform extension 184 is generally circularly shaped and the opening 186 is formed through a central portion thereof.

The platform extension 184 includes a plurality of flanges 188, one end of each of the flanges 188 being secured to a top portion 190 of the platform extension 184 and the opposite end of each of the flanges 188 extending a distance radially beyond the outer periphery of the platform extension 184. The flanges 188 are spaced circumferentially about the outer periphery of the platform extension 184 and, in an assembled position of the platform extension 184, the platform extension 184 is disposed generally within the opening 36 through the well drilling rig platform 12 and'the end of each of the flanges 188, opposite the ends thereof secured to the platform extension 184, engages a portion of the well drilling rig platform 12 generally adjacent the opening 36 cooperating with the well drilling rig platform 12 to support the platform extension 184 in an assembled position over the opening 36.

Utilizing the platform extension 184, the platform extension v184 is disposed in an assembled position within the opening 36 and supported on a portion of the well drilling rig platform 12 or, more particularly, on the portion 38 of the well drilling rig platform 12 via the flanges 188 and the safety guard 10 is positioned and supported on the platform extension 184, the lower end 50 of the cage 44 being supported on the top portion 190 of the platform extension 180, in one operating position of the safety guardlO. Since the platform extension 184 forms an extended portion of the platform 12, the support extension 184 is sometimes generally referred to herein as the well drilling rig platform, the safety guard 10 being supported in a stationary position on the well drilling rig platform 12 via the extended portion thereof formed via the platform extension 184.

As shown more clearly in FIGS. 3 and 6, the safety guard 10 also includes a support rim 192 extending annularly about the outer peripheral surface 58 of the cage wall 46 and spaced a distance from the lower end 50 of the cage wall 46, thereby forming an annularly downwardly facing surface 194. In a preferred form, the diameter of the cage 44 is smaller than the diameter of the opening 186 such that a portion of the cage 44 extends through the opening 186 to a position wherein the downwardly facing surface 194 engages a portion of the top 190 of the platform extension 184 limiting the downward movement of the cage 44 and positioning the safety guard 10 in a predetermined assembled position on the well drilling rig platform 12 or, more particularly, the platfomi extension 184. In this assembled position of the safety guard 10, the transverse movement of the safety guard 10 is substantially prevented via the engagement between the portion of the outer peripheral surface 58 of the cage wall 46 generally below the support rim 192 and the portion of the platform extension 184 formed via the opening 186 therethrough, thereby positively locating the safety guard 10 in an assembled position.

EMBODIMENT OF FIGS. 8, 9 AND 10 Shown in FIGS. 8, 9 and 10 is a modified safety guard 10a having a modified cage 44a comprised of a modified first cage segment 66a and a modified second cage segment 68a. The cage 44a is cylindrically shaped, similar to the cage 44 described before, the salient difference between the cage 44 and the modified cage 44a being the construction and assembly of the first and the second cage segments 66a and 68a.

The first cage segment 66a is arcuately shaped and the inner and the outer peripheral surfaces 58a and a each extend a distance circumferentially greater than 180 terminating with opposite edges a and 82a. Thus, the first cage segment 66a comprises a portion of the cage 44a substantially greater than one-half of the entire cage 44a. A channel flange 200 is secured to the outer peripheral surface 58a generally adjacent the edge 80a and extending a distance therefrom, and a channel flange 202 is secured to the inner peripheral surface 60a generally adjacent the edge 80a and extending a distance therefrom. The extended portions of the channel flanges 200 and 202 are spaced a distance apart via the thickness of the cage wall 46a and cooperate with the edge 80a to form a first channel 204 extending along the edge 80a generally between the upper and the lower ends 48a and 50a of the cage wall 46a. A channel flange 206 is secured to the outer peripheral surface 58a generally adjacent the edge 82a and extending a distance therefrom, and a channel flange 208 is secured to the inner peripheral surface 60a generally adjacent the edge 82a and extending a distance therefrom. The extended portions of the channel flanges 206 and 208 are spaced a distance apart via the thickness of the cage wall 46a and cooperate with the edge 82a to form a second channel 210 extending along the edge 82a generally between the upper and the lower ends 48a and 50a of the cage wall 46a.

The second cage segment 68a is arcuately shaped and extends a distance between the opposite edges 94a and 96a sufficient to encompass the space between the edges 80a and 82a of the first cage segment 66a, the first and the second cage segments 66a and 68a cooperating to form the cage 44a in a manner similar to that described before with respect to the first and the second cage segments 66 and 68 of the cage 44. More particularly, the first channel 206 is sized to slidingly receive and retainingly encompass a portion of the second cage segment 66a generally adjacent the edge 94a and the second channel 210 is sized to slidingly receive and retainingly encompass a portion of the second cage segment 66a generally adjacent the edge 96a.

Thus, the second cage segment 68a is disposed generally near the upper end 72a of the first cage segment 66a and the lower end 88a of the second cage segment 68a generally adjacent the edges 94a and 96a is disposed generally within the first and the second channels 204 and 210. The second cage segment 68a is then slid in a downwardly direction 212 to an assembled position connecting the first and the second cage segments 66a and 68a to form the cage 44a.

The first plate segment 116a forms a portion of the cage plate 52a substantially greater than one-half of the total area encompassed via the cage plate 52a, the second plate segment 118a being smaller than the first plate segment 116a and forming the remaining portion of the cage plate 52a in an assembled position of the first and the second cage segments 66a and 68a. A stop flange 214 is secured to the lower surface of the first plate segment 1 16a, a portion of the stop flange 214 extending a distance beyond the plate edge 120a, as shown in FIG. 9. A stop flange 216 is also secured to the bottom of the first plate segment 116a, a portion of the stop flange 216 extending a distance beyond the portion of the plate edge 124a disposed generally on the opposite side of the arcuately shaped portion 122a with respect to the disposition of the plate edge 120a.

The stop flanges 214 and 216 are each positioned to provide upwardly facing surfaces 218 and 220, respectively, each extending a distance into the space between the plate edges 120a and 124a and each engaging portions of the second plate segment 1 18a generally near one of the plate edges 120a and 124a limiting the movement of the second cage segment 68a in a direction 212. Thus, the second cage segment 68a is disposed in a position wherein portions thereof generally adjacent the edges 94a and 96a are disposed in one of the first and the second channels 204 and 210, as shown in FIG. 10, and the second cage segment 68a is slid downwardly in a direction 212 to a position wherein portions of the second plate segment 1 18a generally adjacent the edges 94a and 96a each engage one of the upwardly facing surfaces 218 and 220 positioning the first and the second cage segments 66a and 68a in an assembled position forming the cage 44a.

As shown in FIG. 9, the plate edge 120a of the first plate segment 116a includes a pair of inwardly formed portions 222 and 224, the inwardly formed portion 222 being formed on one side of the arcuately shaped portion 122a and the inwardly shaped portion 224 being formed on the opposite side of the arcuately shaped portion 122a. Each inwardly shaped portion 222 and 224 forms an engaging surface 226. The second plate segment 118a includes a pair of flange lock portions 228 and 230, the flange lock portion 228 being formed on one side of the arcuately shaped portion 126a and the flange lock portion 230 being formed on the opposite side of the arcuately shaped portions 126a. Each flange lock portion 230 forms an engaging surface 232 engageable with one of the engaging surfaces 226 formed via the inwardly formed portions 222 and 224 further limiting the movement of the second cage segment 68a in a direction 234, thereby cooperating with the first and the second channels 204 and 210 to restrain and secure the first and the second cage segments 66a and 66a in an assembled position.

The first and the second channels 204 and 210 and the locking engagement between the engaging surfaces 226 and 232 thus form a portion of a modified lock assembly 98a for securing the first and the second cage segments 66a and 68a in a secured, assembled position. The lock assembly 98a also includes a first tube 236 secured to the top of the first plate segment 116a and a second tube 238 secured to the top of the second plate segment 118a. Each of the tubes 236 and 238 have an opening (not shown) formed axially therethrough, the openings (not shown) being aligned in an assembled position of the first and the second cage segments 1 16a and 118a. A rod 240, having a flange 242 formed on one end thereof, is insertable through the aligned openings (not shown) through the first and the second tubes 236 and 238, the flange 242 engaging the first tube 236 to limit the movement of the rod 240 in a direction 244 through the first and the second tubes236 and 238. One end of a chain 246 is secured to the first plate segment 116a and the opposite end of the chain 246 is removably secured to the end of the rod 240, opposite the flange 242 end thereof, the chain 246 securing the rod 240 in an assembled position through the openings (not shown) of the first and the second tubes 236 and 238 thereby further cooperating to secure the first and the second cage segments 66a and 68a in an assembled, locked position.

A handle 248 is secured to the outer peripheral surface 58a generally near the upper end 86a of the second cage segment 68a. The handle 248 is utilized to facilitate the handling of the second cage segment 68a and the insertion thereof into an assembled position with respect to the first cage segment 66a in a manner described before. It should also be noted that handles are secured to the first and the second cage segments The safety guards 10 and 10a are thus each constructed to be securedly connected in a locked, assembled position in a fast and efficient manner and in a manner in which the safety guards 10 and 10a can also be disassembled in a fast and efficient manner. The safety guards 10 and 10a are each supported in a stationary position protectively encompassing the opening 36 through the well drilling rig platform 12, the Kelly 18, the rotary drive bushing 14 and portions of the rotary table 16 in a drilling position of the well drilling rig apparatus, thereby substantially preventing chains and wash-down hoses and the like from becoming entangled in the well drilling rig apparatus encompassed via the safety guards l and a and substantially preventing injuries to the well drilling rig personnel resulting from slipping into the rotary table 16 or other well drilling rig apparatus encompassed via the safety guards 10 and 10a.

Changes may be made in the various components and assemblies of the present invention disclosed herein without departing from the spirit and the scope of the invention as defined in the following claims.

What is claimed is:

l. A safety guard for use on a well drilling rig platform protectively guarding portions of a rotary table, portions of a well drilling rig Kelly and portions of a rotary drive bushing, the rotary drive bushing being connected to a portion of the Kelly and engageable with a portion of the rotary table and the rotary table imparting rotary motion to the Kelly via the rotary drive bushing in one position, the safety guard comprising:

a cage wall having an upper end, a lower end, an inner peripheral surface forming a cage opening extending through the cage wall intersecting portions of the upper and the lower ends thereof, and an outer peripheral surface; and

means having a portion engaging the lower end portion of the cage wall and a portion engaging a portion of the well drilling rig platform supporting the cage wall on the well drilling rig platform generally above a portionof the rotary table, a portion of said means having an opening therethrough providing communication with a portion of the rotary table in one position, the cage opening being in communication with the rotary table via the opening in said means and a portion of the kelly extending through the cage opening and through the opening in said means, a portion of the Kelly and the rotary drive bushing connected thereto extending through the cage opening, said means removably supporting the cage wall ina stationary position with the inner peripheral surface of the cage wall surrounding a portion of the rotary drive bushing during the rotation of the Kelly 'via the rotary motion imparted to the rotarydrive bushing via the rotary table.

2. The safety guard of claim 1 defined further to include: v

a cage plate connected to the upper end of the cage wall extending generally over and encompassing a portion of the cage opening at the upper end of the cage wall, a Kelly opening formed through a portion of the cage plate, a portion of the Kelly disposed through the Kelly opening and the inner peripheral surface of the cage wall surrounding a portion of the rotary drive bushing partially disposed within a portion of the cage opening in one operating position of the safety guard.

3. The safety guard of claim 2 wherein the Kelly opening through the cage plate is defined further as being of a size smaller than the size of the rotary drive bushing, the cage plate engaging the rotary drive bushing andthe safety guard being supportable via the engagement between the cage plate and the rotary drive bushing in one operating position of the safety guard.

4. The safety guard of claim 1 wherein the cage wall includes:

a first cage segment having an upper end, a lower end, opposite edges and forming a portion of the cage wall;

a second cage segment having an upper end, a lower end and opposite edges, the opposite edges of the second cage segment engaging the opposite edges of the first cage segment and the second and the first cage segments forming the cage wall in an assembled position thereof; and

means having a portion connectable to the first cage segment and a portion connectable to the second cage segment removably securing the first and the secon cage segments in an assembled position.

5. The safety guard of claim 4 defined further to include:

a first plate segment connected to the upper end portion of the first cage segment, having a plate edge extending between the opposite edges of the first plate segment and an arcuately shaped portion formed in a portion of the plate edge of the first plate segment; and

second plate segment connected to the upper end portion of the second cage segment having a plate edge extending between the opposite edges of the second plate segment and an arcuately shaped portion formed in a portion of the plate edge of the second plate segment, the plate edge of the second plate segment disposed generally near the plate edge of the first plate segment and the arcuately shaped portions of the first and the second plate segments cooperating to form a Kelly opening communicating with the cage opening in an assembled position of the first and the second cage segments.

6. The safetyguard of claim 4 wherein the means removably securing the first and the second cage segments in an assembled position is defined further to include:

a first vertical hinge assembly having portions connecting one edge of the first cage segment to one edge of the second cage segment, comprising: first'hinge element means connected to the first cage segment generally near one edge thereof, the first hinge element means having a hinge opening extending therethrough;

I second hinge element means connected to the second cage segment generally near one edge thereof, the second hinge element means having a hinge opening extending therethrough, the

. hinge opening of the first hinge element means aligned with the hinge opening of the second hinge element means in an assembled position of the first and the second cage segments; and

vertical rod means having a portion insertable through the aligned hinge openings of the first and the second hinge element means connecting ing a hinge opening extending therethrough, the hinge opening of the first hinge element means aligned with the hinge opening of the second hinge element means in an assembled position of the first and the second cage segments; and

vertical rod means having a portion insertable through the aligned hinge openings of the first the one edge of the first cage segment to one edge of the second cage segment via the first and the second hinge element means and the vertical rod means.

7. A safety guard for use on an oil well drilling rig 5 platfomi protectively guarding portions of a rotary table, the safety guard comprising:

a cage wall having an upper end, a lower end, an

inner peripheral surface forming a cage opening and the second hinge element means connectextending through the cage wall intersecting por- 10 ing the one edge of the first cage segment to tions of the upper and the lower ends thereof, and one edge of the second cage segment via the an outer peripheral surface, the lower end of the first and the second hinge element means and cage wall supportable via the well drilling rig platthe vertical rod means.

form in a stationary position and the cage opening 8. A safety guard for use on a well drilling rig platproviding communication with the rotary table via form protectively guarding portions of a rotary table,

the upper end of the cage wall in one operating position of the safety guard, the cage wall including: first cage segment having an upper end, a lower end, opposite edges and forming a portion of the second hinge element means connected to the second cage segment generally near one edge thereof, the second hinge element means havthe safety guard comprising:

a cage wall having an upper end, a lower end, an inner peripheral surface forming a cage opening extending through the cage wall intersecting porcage wall; tions of the upper and the lower ends thereof, and second cage segment having an upper end, a lower an outer peripheral surface, the lower end of the end and opposite edges, the opposite edges of the cage wall supportable via the well drilling rig platsecond cage segment engaging the opposite edges form in a stationary position and the cage opening of the first cage segment and the second and the providing communication with the rotary table via first cage segments forming the cage wall in an asthe upper end of the cage wall in one operating posembled position thereof; sition of the safety guard, comprising: means having a portion connectable to the first cage a first cage segment having an upper end, a lower segment and a portion connectable to the second end, opposite edges and forming a portion of a cage cage segment removably securing the first and secwall; and ond cage segments in an assembled position, coma second cage segment having an upper end, a lower prising: end and opposite edges, the opposite edges of the a first vertical hinge assembly having portions consecond cage segment engaging the opposite edges necting one edge of the first cage segment to one of the first cage segment and the first and the secedge of the second cage segment, comprising: ond cage segments forming the cage wall in an asfirst hinge element means connected to the first sembled position thereof;

cage segment generally near one edge thereof, means having a portion connectable to the first cage the first hinge element means having a hinge segment and a portion connectable to the second opening extending therethrough; cage segment removably securing the first and the second hinge element means connected to the second cage segments in an assembled position,

second cage segment generally near one edge comprising: thereof, the second hinge element means hava first vertical hinge assembly having portions coning a hinge opening extending therethrough, necting one edge of the first cage segment to one the hinge opening of the first hinge element edge of the second cage segment, comprising: means aligned with the hinge opening of the first hinge element means connected to the first second hinge element means in an assembled cage segment generally near one edge thereof, position of the first and the second cage segthe first hinge element means having a hinge ments; and opening extending therethrough; vertical rod means having a portion insertable second hinge element means connected to the through the aligned hinge openings of the first second cage segment'generally near one edge and the second hinge element means connectthereof, the second hinge element means having the one edge of the first cage segment to ing a hinge opening extending therethrough, one edge of the second cage segment via the the hinge opening of the first hinge element first and the second hinge element means and means aligned with the hinge opening of the the vertical rod means; 5 5 second hinge element means in an assembled a second hinge assembly having portions connect position of the first and the second cage seging one edge of the first cage segment to one ments; and edge of the second cage segment, opposite the vertical rod means having a portion insertable edges of the first and the second cage segments through the aligned hinge openings of the first connected via the first hinge assembly, the secand the second hinge element means connectond hinge assembly comprising: ing the one edge of the first cage segment to first hinge element means connected to the first one edge of the second cage segment via the cage segment generally near one edge thereof, first and the second hinge element means and the first hinge element means having a hinge the vertical rod means, an angled portion being opening extending therethrough; formed on one end of the vertical rod means,

generally opposite the end portion insertable through the hinge openings of the first and the second hinge element means, the angled por- 21 tion engaging one of the first and the second hinge element means limiting the movement of the vertical rod means in one direction through the hinge openings; 7

a first plate segment connected tothe upper end portion of the first cage segment, having a plate edge extending between the opposite edges of the first plate segment and an arcuately shaped portion formed in a portion of the plate edge of the first plate segment; and second plate segment connected to the upper end portion of the second cage segment, having a plate edge extending between the opposite edges of the second plate segment and an arcuately shaped portion formed in a portionof the plate edge of the second plate segmentrdisposed generally near the plate edge of the first plate segment and the arcuately shaped portions of the first and the second plate segments cooperating to form a Kelly opening communicating with the cage opening in an assembled position of the first and the second cage segments; and a horizontal hinge assembly having portions connecting the plate edges of the first and the second plate segments, comprising: first plate hinge element means connected to the first plate segment generally near the plate edge thereof and having a plate hinge opening formed therethrough; second plate hinge element means connected to the second plate segment generally near the edge thereof and having a plate hinge opening formed therethrough, the plate hinge opening of the second plate hinge element means aligned with the plate hinge opening of the first plate hinge element means in an assembled-position of the first and the second cage segments; and

horizontal rod means having a portion insertable through the aligned plate hinge openings of the first and the second plate hinge element means cooperatingly connecting the plate edges of the first and the second plate segments in an assembled position, the horizontal rod means having an angled portion engaging one of the first and the second plate hinge element means limiting the movement of the horizontal rod means in one direction through the plate hinge openings.

9. The safety guard of claim 8 wherein the angled portion of the vertical rod means is disposed near the angled portion of the horizontal rod means and engageable therewith to limit the movement of the horizontal rod means in a direction generally opposite the direction limited via the engagement between the angled portion of the horizontal rod means and one of the first and the second plate hinge element means, thereby securing the horizontal rod means in an assembled position inserted through the plate hinge openings of the first and the second plate hinge element means.

10. The safety guard of claim 9 wherein the means removably securing the first and the second cage segments in an assembled position is defined further to include:

chain means having one end portion secured to a portion of one of the first and the second plate segments and the opposite end portion thereof removably connectable to the vertical rod means limiting the movement of the vertical rod means in a direction generally opposite the direction of movement limited via the engagement between the angled portion of the vertical rod means and one of the first and the second hinge element means.

11. The safety guard of claim 1 wherein the means supporting the cage wall on the well drilling rig platform is defined further to include:

a platform extension having a top surface engageable with the lower end portion of the cage wall supporting the cage wall in one position, the platform extension having an opening therethrough providing communication with a portion of the rotary table in one position of the platform extension; and

means having a portion connected to the platform extension and a portion removably connectable to a portion of the well drilling rig platform for supporting the cage wall on the well drilling rig platform via the platform extension in in a stationary position during the rotation of the Kelly and the rotary drive bushing.

12. A safety cage for use on an oil well drilling rig platform protectively guarding portions of a rotary table, the safety guard comprising:

a cage wall havingran upper end, a lower end, an inner peripheral surface forming a cage opening extending through the cage wall intersecting portions of the upper and the lower ends thereof, and an outer peripheral surface, the lower end of the cage wall supportable via the well drilling rig platform in a stationary position and the cage opening providing communication with the rotary table via the upper end of the cage wall in one operating position of the safety guard;

a platform extension having a top surface engageable with the lower end portion of the cage wall supporting the cage wall in one position, the platform extension having an opening therethrough providing communication with a portion of the rotary table in one position of the platform extension; and

means having a portion connected to the platform extension and a portion removably connectable to a portion of the well drilling rig platform, the cage wall being supported on the well drilling rig platform via the platform extension in one position,

comprising:

a support rim secured to a portion of the outer peripheral surface of the cage wall forming a downwardly facing surface, the lower end portion of the cage wall being insertable through the opening in the platform extension and the downwardly facing surface of the support rim engaging a portion of the outer surface of the platform extension limiting the movement of the lower end of the cage wall through the opening in the platform extension, a portion of the outer peripheral surface of the cage wall, generally between the lower end thereof and the support rim, being engageable with a portion of the platform extension formed via the opening therethrough limiting the movement of the cage wall in a direction gener ally transverse to the opening through the platform extension. 13. A safety guard for use on a well drilling rig plat- 5 form protectively guarding portions of a rotary table,

extending through the cage wall intersecting portions of the upper and the lower ends thereof, and

an outer peripheral surface, the cage wall comprising:

afirst cage segment having an upper end, a lower end, opposite edges and forming a portion of the cage wall;

a second cage segment having an upper end, a lower end and opposite edges, the opposite edges of the second cage segment engaging the opposite edges of the first cage segment and the second and the first cage segments forming the cage wall in an assembled position thereof;

first channel means connected to one edge of the first cage segment retainingly receiving a portion of the second cage segment generally near one of the opposite edges thereof in one position thereof; and

second channel means connected to one edge of the first cage segment, opposite the edge connected to the first channel means, retainingly receiving a portion of the second cage segment generally near the edge thereof opposite the edge portion retainingly received via the first channel means.

14. The safety guard of claim 13 defined further to include:

stop plate means connected to a portion of the first cage segment engaging a portion of the second cage segment limiting the movement of the second cage segment in one direction and cooperating to position the first and the second cage segments in an assembled position; and

means having a portion removably connectable to a portion of the first and the second cage segments limiting the movement of the second cage segment in a direction generally opposite the direction limited via the stop plate means to lockingly secure the first and the second cage segments in an assembled position. 

1. A safety guard for use on a well drilling rig platform protectively guarding portions of a rotary table, portions of a well drilling rig Kelly and portions of a rotary drive bushing, the rotary drive bushing being connected to a portion of the Kelly and engageable with a portion of the rotary table and the rotary table imparting rotary motion to the Kelly via the rotary drive bushing in one position, the safety guard comprising: a cage wall having an upper end, a lower end, an inner peripheral surface forming a cage opening extending through the cage wall intersecting portions of the upper and the lower ends thereof, and an outer peripheral surface; and means having a portion engaging the lower end portion of the cage wall and a portion engaging a portion of the well drilling rig platform supporting the cage wall on the well drilling rig platform generally above a portion of the rotary table, a portion of said means having an opening therethrough providing communication with a portion of the rotary table in one position, the cage opening being in communication with the Rotary table via the opening in said means and a portion of the kelly extending through the cage opening and through the opening in said means, a portion of the Kelly and the rotary drive bushing connected thereto extending through the cage opening, said means removably supporting the cage wall ina stationary position with the inner peripheral surface of the cage wall surrounding a portion of the rotary drive bushing during the rotation of the Kelly via the rotary motion imparted to the rotary drive bushing via the rotary table.
 2. The safety guard of claim 1 defined further to include: a cage plate connected to the upper end of the cage wall extending generally over and encompassing a portion of the cage opening at the upper end of the cage wall, a Kelly opening formed through a portion of the cage plate, a portion of the Kelly disposed through the Kelly opening and the inner peripheral surface of the cage wall surrounding a portion of the rotary drive bushing partially disposed within a portion of the cage opening in one operating position of the safety guard.
 3. The safety guard of claim 2 wherein the Kelly opening through the cage plate is defined further as being of a size smaller than the size of the rotary drive bushing, the cage plate engaging the rotary drive bushing and the safety guard being supportable via the engagement between the cage plate and the rotary drive bushing in one operating position of the safety guard.
 4. The safety guard of claim 1 wherein the cage wall includes: a first cage segment having an upper end, a lower end, opposite edges and forming a portion of the cage wall; a second cage segment having an upper end, a lower end and opposite edges, the opposite edges of the second cage segment engaging the opposite edges of the first cage segment and the second and the first cage segments forming the cage wall in an assembled position thereof; and means having a portion connectable to the first cage segment and a portion connectable to the second cage segment removably securing the first and the secon cage segments in an assembled position.
 5. The safety guard of claim 4 defined further to include: a first plate segment connected to the upper end portion of the first cage segment, having a plate edge extending between the opposite edges of the first plate segment and an arcuately shaped portion formed in a portion of the plate edge of the first plate segment; and a second plate segment connected to the upper end portion of the second cage segment having a plate edge extending between the opposite edges of the second plate segment and an arcuately shaped portion formed in a portion of the plate edge of the second plate segment, the plate edge of the second plate segment disposed generally near the plate edge of the first plate segment and the arcuately shaped portions of the first and the second plate segments cooperating to form a Kelly opening communicating with the cage opening in an assembled position of the first and the second cage segments.
 6. The safety guard of claim 4 wherein the means removably securing the first and the second cage segments in an assembled position is defined further to include: a first vertical hinge assembly having portions connecting one edge of the first cage segment to one edge of the second cage segment, comprising: first hinge element means connected to the first cage segment generally near one edge thereof, the first hinge element means having a hinge opening extending therethrough; second hinge element means connected to the second cage segment generally near one edge thereof, the second hinge element means having a hinge opening extending therethrough, the hinge opening of the first hinge element means aligned with the hinge opening of the second hinge element means in an assembled position of the first and the second cage segments; and vertical rod means having a portion insertable through the aligned hinge openings of tHe first and the second hinge element means connecting the one edge of the first cage segment to one edge of the second cage segment via the first and the second hinge element means and the vertical rod means.
 7. A safety guard for use on an oil well drilling rig platform protectively guarding portions of a rotary table, the safety guard comprising: a cage wall having an upper end, a lower end, an inner peripheral surface forming a cage opening extending through the cage wall intersecting portions of the upper and the lower ends thereof, and an outer peripheral surface, the lower end of the cage wall supportable via the well drilling rig platform in a stationary position and the cage opening providing communication with the rotary table via the upper end of the cage wall in one operating position of the safety guard, the cage wall including: a first cage segment having an upper end, a lower end, opposite edges and forming a portion of the cage wall; a second cage segment having an upper end, a lower end and opposite edges, the opposite edges of the second cage segment engaging the opposite edges of the first cage segment and the second and the first cage segments forming the cage wall in an assembled position thereof; means having a portion connectable to the first cage segment and a portion connectable to the second cage segment removably securing the first and second cage segments in an assembled position, comprising: a first vertical hinge assembly having portions connecting one edge of the first cage segment to one edge of the second cage segment, comprising: first hinge element means connected to the first cage segment generally near one edge thereof, the first hinge element means having a hinge opening extending therethrough; second hinge element means connected to the second cage segment generally near one edge thereof, the second hinge element means having a hinge opening extending therethrough, the hinge opening of the first hinge element means aligned with the hinge opening of the second hinge element means in an assembled position of the first and the second cage segments; and vertical rod means having a portion insertable through the aligned hinge openings of the first and the second hinge element means connecting the one edge of the first cage segment to one edge of the second cage segment via the first and the second hinge element means and the vertical rod means; a second hinge assembly having portions connecting one edge of the first cage segment to one edge of the second cage segment, opposite the edges of the first and the second cage segments connected via the first hinge assembly, the second hinge assembly comprising: first hinge element means connected to the first cage segment generally near one edge thereof, the first hinge element means having a hinge opening extending therethrough; second hinge element means connected to the second cage segment generally near one edge thereof, the second hinge element means having a hinge opening extending therethrough, the hinge opening of the first hinge element means aligned with the hinge opening of the second hinge element means in an assembled position of the first and the second cage segments; and vertical rod means having a portion insertable through the aligned hinge openings of the first and the second hinge element means connecting the one edge of the first cage segment to one edge of the second cage segment via the first and the second hinge element means and the vertical rod means.
 8. A safety guard for use on a well drilling rig platform protectively guarding portions of a rotary table, the safety guard comprising: a cage wall having an upper end, a lower end, an inner peripheral surface forming a cage opening extending through the cage wall intersecting portions of the upper and the lower ends thereof, and an outer peripheral surface, the lower end of the cage wall supportable via the well drilling rig plAtform in a stationary position and the cage opening providing communication with the rotary table via the upper end of the cage wall in one operating position of the safety guard, comprising: a first cage segment having an upper end, a lower end, opposite edges and forming a portion of a cage wall; and a second cage segment having an upper end, a lower end and opposite edges, the opposite edges of the second cage segment engaging the opposite edges of the first cage segment and the first and the second cage segments forming the cage wall in an assembled position thereof; means having a portion connectable to the first cage segment and a portion connectable to the second cage segment removably securing the first and the second cage segments in an assembled position, comprising: a first vertical hinge assembly having portions connecting one edge of the first cage segment to one edge of the second cage segment, comprising: first hinge element means connected to the first cage segment generally near one edge thereof, the first hinge element means having a hinge opening extending therethrough; second hinge element means connected to the second cage segment generally near one edge thereof, the second hinge element means having a hinge opening extending therethrough, the hinge opening of the first hinge element means aligned with the hinge opening of the second hinge element means in an assembled position of the first and the second cage segments; and vertical rod means having a portion insertable through the aligned hinge openings of the first and the second hinge element means connecting the one edge of the first cage segment to one edge of the second cage segment via the first and the second hinge element means and the vertical rod means, an angled portion being formed on one end of the vertical rod means, generally opposite the end portion insertable through the hinge openings of the first and the second hinge element means, the angled portion engaging one of the first and the second hinge element means limiting the movement of the vertical rod means in one direction through the hinge openings; a first plate segment connected to the upper end portion of the first cage segment, having a plate edge extending between the opposite edges of the first plate segment and an arcuately shaped portion formed in a portion of the plate edge of the first plate segment; and a second plate segment connected to the upper end portion of the second cage segment, having a plate edge extending between the opposite edges of the second plate segment and an arcuately shaped portion formed in a portion of the plate edge of the second plate segment disposed generally near the plate edge of the first plate segment and the arcuately shaped portions of the first and the second plate segments cooperating to form a Kelly opening communicating with the cage opening in an assembled position of the first and the second cage segments; and a horizontal hinge assembly having portions connecting the plate edges of the first and the second plate segments, comprising: first plate hinge element means connected to the first plate segment generally near the plate edge thereof and having a plate hinge opening formed therethrough; second plate hinge element means connected to the second plate segment generally near the edge thereof and having a plate hinge opening formed therethrough, the plate hinge opening of the second plate hinge element means aligned with the plate hinge opening of the first plate hinge element means in an assembled position of the first and the second cage segments; and horizontal rod means having a portion insertable through the aligned plate hinge openings of the first and the second plate hinge element means cooperatingly connecting the plate edges of the first and the second plate segments in an assembled position, the horizontal rod means having an angled portion engaging one of the first and the second plate hinge elemeNt means limiting the movement of the horizontal rod means in one direction through the plate hinge openings.
 9. The safety guard of claim 8 wherein the angled portion of the vertical rod means is disposed near the angled portion of the horizontal rod means and engageable therewith to limit the movement of the horizontal rod means in a direction generally opposite the direction limited via the engagement between the angled portion of the horizontal rod means and one of the first and the second plate hinge element means, thereby securing the horizontal rod means in an assembled position inserted through the plate hinge openings of the first and the second plate hinge element means.
 10. The safety guard of claim 9 wherein the means removably securing the first and the second cage segments in an assembled position is defined further to include: chain means having one end portion secured to a portion of one of the first and the second plate segments and the opposite end portion thereof removably connectable to the vertical rod means limiting the movement of the vertical rod means in a direction generally opposite the direction of movement limited via the engagement between the angled portion of the vertical rod means and one of the first and the second hinge element means.
 11. The safety guard of claim 1 wherein the means supporting the cage wall on the well drilling rig platform is defined further to include: a platform extension having a top surface engageable with the lower end portion of the cage wall supporting the cage wall in one position, the platform extension having an opening therethrough providing communication with a portion of the rotary table in one position of the platform extension; and means having a portion connected to the platform extension and a portion removably connectable to a portion of the well drilling rig platform for supporting the cage wall on the well drilling rig platform via the platform extension in in a stationary position during the rotation of the Kelly and the rotary drive bushing.
 12. A safety cage for use on an oil well drilling rig platform protectively guarding portions of a rotary table, the safety guard comprising: a cage wall having an upper end, a lower end, an inner peripheral surface forming a cage opening extending through the cage wall intersecting portions of the upper and the lower ends thereof, and an outer peripheral surface, the lower end of the cage wall supportable via the well drilling rig platform in a stationary position and the cage opening providing communication with the rotary table via the upper end of the cage wall in one operating position of the safety guard; a platform extension having a top surface engageable with the lower end portion of the cage wall supporting the cage wall in one position, the platform extension having an opening therethrough providing communication with a portion of the rotary table in one position of the platform extension; and means having a portion connected to the platform extension and a portion removably connectable to a portion of the well drilling rig platform, the cage wall being supported on the well drilling rig platform via the platform extension in one position, comprising: a support rim secured to a portion of the outer peripheral surface of the cage wall forming a downwardly facing surface, the lower end portion of the cage wall being insertable through the opening in the platform extension and the downwardly facing surface of the support rim engaging a portion of the outer surface of the platform extension limiting the movement of the lower end of the cage wall through the opening in the platform extension, a portion of the outer peripheral surface of the cage wall, generally between the lower end thereof and the support rim, being engageable with a portion of the platform extension formed via the opening therethrough limiting the movement of the cage wall in a direction generally transverse to the opening through thE platform extension.
 13. A safety guard for use on a well drilling rig platform protectively guarding portions of a rotary table, the safety guard comprising: a cage wall having an upper end, a lower end, an inner peripheral suruface forming a cage opening extending through the cage wall intersecting portions of the upper and the lower ends thereof, and an outer peripheral surface, the cage wall comprising: a first cage segment having an upper end, a lower end, opposite edges and forming a portion of the cage wall; a second cage segment having an upper end, a lower end and opposite edges, the opposite edges of the second cage segment engaging the opposite edges of the first cage segment and the second and the first cage segments forming the cage wall in an assembled position thereof; first channel means connected to one edge of the first cage segment retainingly receiving a portion of the second cage segment generally near one of the opposite edges thereof in one position thereof; and second channel means connected to one edge of the first cage segment, opposite the edge connected to the first channel means, retainingly receiving a portion of the second cage segment generally near the edge thereof opposite the edge portion retainingly received via the first channel means.
 14. The safety guard of claim 13 defined further to include: stop plate means connected to a portion of the first cage segment engaging a portion of the second cage segment limiting the movement of the second cage segment in one direction and cooperating to position the first and the second cage segments in an assembled position; and means having a portion removably connectable to a portion of the first and the second cage segments limiting the movement of the second cage segment in a direction generally opposite the direction limited via the stop plate means to lockingly secure the first and the second cage segments in an assembled position. 